Fluid pressure system



. Marc}! 1944. s. SCHNELL 2,343809 FLUID PRESSURE SYSTEM Fiied Jan. 14,1942 INVENTOR ATH'ORNEY aeme am 7, 19

FL PRESSE SYSTEM Steve Schnell, Kirkwoo, Mo. assignor to Wagner ElectricCorporaion, St. Louis, Mo., a corporation oi Delaware Appliction JanuaryM, 1942, Serial N0. 426,699

14 Claims.

My inventlon relates 120 fluid pr essure systems and more particularkv120 valve means for co'ntrolfing said systems.

ne cf the objects of my invention is to produce an improved fluidpress'ure system wherein the fiuid pressure employed to actuate a devicecan be trapped therein when desired and automat:lcally released byre-appllcation of pressure from the pressure source.

Another obje ct of my invention is to produce an jmproved valve meansfor preventing the re- .Jease of applied fiuid pressure which is causedto be operative by manually-controlled means and inoperative bo therebyrelease bhe applied fluid pressure by merely again applying pressure.

Still anothe1y object cf my Invention is 130 prouce an improved fluidpressure actuating system which has associated therewith valve means forpreventing release o1 the applied pressure and a pressure maintainingIneans which ls onlfv caused i;o be operative when fluid pressure isprevented from being released by the valve means.

Other objects of my invention will become apparent from the followingdescription taken in conn ection with the 'accompanying drawing in whichthe single figure is a schematic view cf a fluid pressure actuatingsystem embodying my lnvention, the control valve being enlarged a'ndshown in section.

Referring to the figure in detail, the mumeral indicates a pressureproducing devicein 3he form of a hydraulic master cyllnder. thepllston 2cf which is actuated by a rod 3 and a S)8dl 43. The device to beactuated is shown as a bmke 5 although it may be any other devicedeslre. A fiuid motor 6 actuates the brake shoe and sald motor isconnected with the master cylinder by conduits 8 and 9 Whi"h haveasscciated therewith my improved control valve mechanism generally lnclicated by th(a numeral II]. The fluid pressure system also hasassociatpd therewith a, pressure maintainer II comprising a ay1inder I2,a piston I3, and a streng spring M acting on the piston. This pressunamaintainer is also Controlled by the cont-rol valve mechani sm I 0 andis adapted to be connected to the fiuid motm 6 only under certainconditions. A conduit I5 leads from the maintainer' H 150 the controlvalve.

My improved control valve merdanism 50 is employed to trap fi uidpressure in the motorfi when deslred and to substantially simultaneouslyccnnect the maintainer to the motor so that said trapped. fluid pressurewill be mainiiained indefinitely notwithstanding contraction of thefiuid due 150 a decrease in temperature all 0f which will becomeapparent.

My improved control valve mechanism co mprises a casing 16 hav1ng athrough bore H formed withenlarg'ed threaded ends {8 and 59 wherebyshoulders 20 and 2i are provided. The threaded end I8 is closed by athreaded cylindriaal plug 22 and the threaded end E3 is closed by athreaded plug 23, the internal diameters of said plugs corresponding tothe central pa-rt of bore !'i. The inner end of p1ug 22 holds an annularwasher 24 between ir and the-shoulder 20, and the inner end of plu 23holds a Iike annular washer 25 between it and the shoulder 25 thusprovide spaced apart abutments.

Associated with the inner side of washer 24 is an annular washer 26forming a Wall for a packing cup 27, and associated with the inner sideof washer 25 is an annular washer 28 forming a Wall for a packing cup'29. The lips of the packing cups face each other and are held againsttheir respective Walls by an interposed spring 3B. The cups 21 and 29,together with the central part of bore I7, form a central chambar 35which is connected by a passage 32 conduit 9 leading to fiuid motor 6.On opDosite sides of this central chamber are end charnbers 33 and 34,chamb er 33 being in plug 22 and end chamber 33 being in plug 23. Agassage 35 counects chamber 33 to conduit 8 leadingfrom the mastercylinder and a passage 36 connects Chamber 33 to conduit 15 Ieading tothe maintainer H Positioned in. chambers 31, 33 and 34 is a rod 31extending 130 the exterior of the cas ing through a packed opening 38 inplug 22. In oraler that the rod may extend through the packing cups,cup.

27 is provided with a tapered or conical aperture 39 and cup 29 isprovided with a tapered or 00mcal aperture 40, both of said apertreshaving their surfaces convergx'ng toward chamber 3I. The central' partof the rod is of reduced diameter and between this portion and the endportions of the rod are conical portions 3! and 32 for cooperation withconical apertures 39 and W, respectively. The con ical portions 4il and32 are spaced apart a greater distance than the conical apertures sothat on1y one of the conical portions can engage its cup cooperatingsurface ab one time.

The end of rod 37 .Which extends into charmber 33 carries a piston 43and associatecl therewith is a. packing cup 44. A spring 5 isintersurface 01 aperture 43 und the conlcal portion 4I is disengagedfrom the surface 01 aperture 33.

In chamber 33 there is positioned. a. piston 43 which is loosely mountedan rod 3'I. Associated wlth this piston is a packlng 41. In order thatthe piston may be movecl from lts normal position where it abuts theclosed end o! plug 22, there is provided on the rod a collar 43, saidcollar abutting the end ot the plug a.nd determiningthe extent etmovement 015 the rod to the left as shown in the ilgure. This collmcanengage piston 43 only after a predetermined movement 01 the rod to theright, seid predetermined movement beim;

less then that necessary to place the conical portion 4I 015 the rod inengagement withthe conical surface of the aperture 39. The end o! therod which extends out o! plug 22' is adapted to be engaged by an arm 49of a bellcra.nk lever 33, said lever being pivottd on a bracket II bymeans o! pin 52. This bracket is secured to the casing by being clampedbetween the casing und plug 22. The bellcranl: lever is operated to movethe rod to the right, es viewed in the flgure, by actuv disengaged irbmthe suriace of the conical aperture 39 in cup 2'I. Thus lt is seen thatcommunication laetween the maintainer II and either the master cylinderor the fluid motor 3 iscut ofi. The master cylinder, however, is in 1reetwoway communication with the fluid motor. Thus ii the master cylinderis operated, the fluld motor will be actuated. When the master cylinderis released by release ot the pedai 4, the fluid under pressure actingin the fluid motor will be released. It is to be noted that when theparts oi the control valve are in the positions shown. there will be noiluid pressure acting an rod 31 to move lt to the right against theiorce o! spring 45. The iluid pressure W hich is eflectlve on theconical portion 42 of the rod tending to move-the rod to the right willbe counter-balanced by an opposite axial force on. the rod caused by thefluid pressure which ls acting on the conical portion 4 I.

II it is desired to trap fluld pressure In fluid motor 3 and to maintainthis fluid pressure for an indefinite period, the bellcrank lever 53isoperated by pull on rod 53 after the master cylinder is operated. Thiswill move rod 31 to the right and cause unseating of the conical pertion42, thereby placing chamber 34 in communicatlon with the central chamber3I. As soon as the fluid pressure is eil'ective in chamber 34 it willact on piston 43 ancl quickly move lt moving the piston I3 thereof backagainst the strong spring I4, thereby compressing said spring. Thus thespring becomes operative to apply a pressure producing t0rce on thefluid in chembers 34 und 3I und the fluid motor 3. 'I'heretore with thepressure malntainer connected into the system. there will be nopossibility oi contraction of the fluid causing the fluid pressure inthe iluid motor to drop to such a low value that the fluid motor willnot be so actuated as to hold the brakes or other device applied.

When lt ls desired to release the trapped fluld pressure in the fluidmotor and also in chambers 3I anal 34, the master cylinder is againoperated and iluid pressure developed'. This developed fluid pressurewill act upon piston 43 and cause lt to move to the leit provided, 015course, that the pressure acting on the piston is suilicient to movepiston 43 against the trapped iluld pressure. Movement 01 piston 46 tothe leit will carry with lt rod 31 (since the piston is abutting collar43) ancl thus Cause the conical portion 4I 01 the rod to becomedisengaged from the suriace 01 the conlcal aperture 33 01 cup 2'I. Assoon es this disengagement takes place the tluid pressure in all thesystem, including chambers 33. 3I and 34, the iluid motor and themalntainer II will become equalized. Under these conditlons spring 43 isefiective to move piston 43 and rod 31 to the to the right as iar aspermissible. This will cause the conicalportion 4I to be brought intoangegev ment with the surface o! the conlcal aperture 39. However, priorto the engagement ot these last mentioned conical suriaces. shoulder 43on the rod will pick up piston 43 und move lt slightly to the right.Because the piston is not picked up by rod 31 until alter it has beenmoved some iistance, the only resista nce to movement of the rod will bespring 45. The master cylinder may now be released a.nd when rel easedthe fluid pres- .auleacting on piston 43 is also released. The

left and to its imperative position shown. The fluid pressure trapped inthe iluid motor will thus be released whenever the pedal of the mastercylinder is released. Fluid pressure whlch may remain in chamber 34 undthe maintainer at the time the conica1 portion 42 becomes seated canescape to the central chamber 3I by pushing cup 4II ofl the conicalportion 42 und against the action o! spring 33 to thus-enter chamber 3Iancl return to the master cylinder.

Thus lt is seen that the trapped fluld may be released automatlcally bydepressing the pedal and operating the master cylinder. Thema is nonecessity for releaslng the pressure by a manual pushing of rod 31 tothe lett ior lt thls were attempted, a. considerable iome would berequlred due to the fact that all the trapped fluld pressure ei!ectiveon piston 43 must be overcome. By applying the m.ster cylinder andcaualng piston 43 to move the rod to the leit by fluid pressure, therelease 01 the trapped fluid pressure ls accom- .pllshed in a verysimple und easy m anner.

- faces. Under these conclitions the cup is 1'ree to move sllghtlyforward agalnst the action o! sprinl 30.

It 1s to be notod that the maintainer II may be eliminated from thesystem if such is deslred'.

Under such an arrangement passage 36 will be plugged. l'he system willthen work in the seime manner as ahead3i describ ed with the exception-that no maintainer will be connected into the system when fiuid istrapped in the fiuid motor to thils compensate for possible contractionof the trapped fiuid.

Being aware of the possibility of modifications in the particularstructure herein described without departing from the fundamentalprinciples of my invention, I do not intend that 1ts scope be limitedexcept as set forth by the appended claims.

Having fully described lny invention, what I claim as new and desire tosecure by Letters Patent cf the United States ist 1. In a fiuid pressurosystem having a source cf pressure anal a fiuid pressure actuated de1ice connected thereto, a chamber provlded with a yieldable Wall, meanscomprising a control valve mechanism operable at will for connecting thechambar to the fiuid pressure actuated device and for substantiallysimultaneously trapping fiuid.under prssure insaid device and in thechamber and thus permitting release of pressure from the source withoutrelease of the' device, and means associated with said control valvemechanism for automatically releasing trapped fiuid pressure am].disconnecting the chamber from said deVice when fiuid pressure from thcsource is again developed anti then re.- leased.

2. In a fiuid pressure System, a sour ce of pressure a fiuid presSureactuated dev1ce, conduit means connecting the source with sa.id device,a chamber having a yieldable wall, valve means 8S*- sociated with saidconduit means for preventing return fiow of fiuid from the actuateddevice and for also automatically placing said device in communicationwith the chamber, means for rendering said valve opezative ab will, andmeans embodied in said va1ve means for automatically causing it 130again assume an inoperative condition only when a fiuid pressure fromthe source is' cleveloped.

3. In a fiuid pressure system, a source cf pressure, a. fiuid pressureactuated device, ionduit means connecting the source with the device, aChamber having a yieldable wall, vahie means associated 'withsaidconduit means for preventlng return fiow of fiuid from the actuateddevice and for connecting thechamber to said device, sald valve meansembodying valve means movable at will to a position olosingcommunication from the device to the source and substantially..fmultaneously cp ening communication between the charmber and saiddevice, mea.ns associatted with the valve means for maintaining sa.idvalve meang in said last named condition by the fiuid pressure efiectivein the actuated device und chaxnber, and m ea.ns for causing seid valvemeans to return to Open position when a. fiuid pressure from Ehe source1s developed.

4. In a fiuid pressure system, a source of pressure. a fiuid pressureactuated device, control means for trapping fiuid under pressure in saiddevic e to thus permit release of pressure at Ehe .source withoufirlease of the device and for also aLutom atically releasing the trappedfiuid under pressre whe'n press1ire is re-applied by the source, saidmeans comprising two valve means having elements coimec :ted to be movedsimultaneously and so relat ed 120 each other thaA;

one of the va.lve means will be closed when the other valve means isopen, one of said valve means when closed trapping fiuid under pressurein the actuated device, metms vcontrolled by the 'other valve mea'nswhen open for permitting the trapped fiuid pressuro to maintain theflrst valve means closed, means for moving Said valve elements ab Willso that the first named valve means 1s closed and the second named valvemeans opened, and means for causing said valve elements to be returned130 positions wherein the first named valve means. is opened and thesecond named valve means is closed whenever a prede. terminecl pressureis .re-applied from the source.

5. In a fiuid pressure system, a source of pressure, a fiuid pressureact;uated d evice, a chamber having a yieldablp wa1l, control means fortrapping fiuid under pressure in said device and connecting the deviceto the chamber 120 thus per'mit release of pressure at the sourcewithout rele'ase of the device am! for also automatlcally releasing thetrapped fiuid under pressure when pressure is re-applied by the sorce,said means coxnprising two valve means ha.ving elements connected to bemoved simultaneously and so related to each other that one-cf the valvemeans will be closed when the other valve means is open, one of seidvalve means when closed. trapping fiuid under pressure in the actuateddevice, means controlled by the other valve means whien operi forpermitting the tr'apped fiuid pressure to maintain the first valvemea.ns closecl and for placing the yieldable wall cham bar incommuhication with the device, mea.ns for moving said valve' elements atwill so tha1:

v the first named valve means is closed and the second named valve meansopened, and means for causing sein! valve elements to be returned topositions wherein the first named valve means is opened and the'secondnamed v'alve means is closed whenever 21. predetermined pressure isreapplied from the source.

6. In. a fiuid pressure system, a source of pressure, a. fluifl pressureactuated device, a chamber having a yieldable wall, control meansfortrapping fiuid under pressure in said device and cannecting the deviceto the chamber to thus permit rlease of pressure a1; the source withoutrelease of the device and for also automatically releasing the trappedfiuid under pressure when pressure is re-applied b v the'source, saidmeans comprisin'g two valve means having elexnents.

connected to be moved simultaneously and so related to each other thatone of the valve means will !oe closed when the other valve means is\013821, one of said valve means when closed trappredetermined pressureis re-applied from the in a closed position.

7. In a fiuid pressure system, a source 01 pressure. fiuid,Pressure-actuated devlce and Conmovable elements 015 said valve meanstosether 1'or simultaneous movement a1; will whereby the fl'rst namedvalve means can be closed und the second valve means opened, a, memberpositioned in the chamber und connected to the movable' elements of thevalve means i;o mainta.in the flrst valve mean8 closed and the secondvalve means open when fluid pressure is admitted to the cha.mblar, undmeans for causing the flrst valv'e means to be open und the second valvemeans to be closed when fluid pressure from 'ohe source is re-applied.

8. In a. fluid pressure system, a. source of pressure, a. fluidpressure-actuated device und coutrol means for trapping fluid underpressure in said device said means comprising a valve means forpreventing when closed retum flow o! fluid from the devlce to the sourcebut not in the oppo site direction, a chamber, a second valve means torpreventing when closed communication between either the source und the-chamber or said device und the chamber but not in the oppositedirection, xnqans for connecting the movable elements of said valvemeans together for simultaneous mo'vement an will whereby the firstnamed vaive mea.ns can be closed and the second vglve means opened, amember positioned in the chamber und connected to the movable elementso! the valve means to maintain.the firsi; valve means closed and thesecond valve means open when fluid pressure is admitted to the chamber,and means for causing the flrst va.lve means to be open und the secondvalve means 120 be closed when fluid pressure from the source isre-a1plied.

said last named mea.ns comprislng a member subject to fluid pressurefrom the source und. so associated with the connected movable elementso1 the two valve means as to move said elements only when the flrstvalve means ls closed and tho second valve means is open.

9. In a fluid pressure system, a source o! pressure, a. fluidpressure-actuated device, a. con-- trol valve mea.ns for trapping fluidunder pressure in said device to thus permit release 015 pressure a.tthe source a.nd for also automatically releasing thetxapped pressurewhen pressure is re-applied from the source, said valve means comprising a. central chamber und two end chambers, said central chamber beingconnect.ed to the actuated device and one end chamber being counected tothe source o1 pressure, a longitudi- 'nally movable member carryingspaced valve elements -spaced valve sea.ts 1'or said elements said valveelements und valve seats being so associated with euch other and thechambers tha.t the central chamber may be alternately conne cted withthe end chambers by a reciprocation cf the longitudinally mova.blemember.

mimual means for mov'ing' said reciprocable member und the vs.lveelements to a position where the central chamber is cut oi! fromcommunication with the'end chamber connected to the source und thecentral chamber is pla.ced

in communication with the Other end chamber,-

nected with the source, mea.ns tor holding seid longitudinal member inthe last name'd posltion by the' trapped fluid pressure, und means iforautomatically returning t he longitudinal member und the valve elementsim a position when the central chamber is in communication with thesource when a predetermined pressure is aga.in applied from the source.

10. In a. fluid pressure system. a. source 01 pressure, a fluidpressure-actuated device, valve means for trapping fluid under pressurein the actuated device anal automatically releasing the same when thepressure is re-apblled from the source, said valve mea.ns comprising 9.central cha.mber connected to the actuated device, end chambers one ofwhich is connected i:o the source of pressure, means comprising a. valveelement for controlling flow ot fluid from the central chmber to one endchamber. means oomprising a valve element for controlling the flow offluid from the central chamber to the other end chamber. means forconnecting said valve elements Ior simultaneous movement so that onevalve elemeni; will be closed when the other is opened, means forbiasing said va.lve elements i;o positions where the end chamberconnected to the source is in communication with the central chamber undthe othervalve element is closed, manually operative means for movingsaid valve elements so that fluid pressure is prevented irom flowingfrom the central cha.mber the source and the other valve element is opento place the end chamber which is not connected to the source incommunication with the central chamber, means for holding said valveelements in the last named position by the fluid pressure trapped in thecentral chamber und the end chamber not connected with the source, andmeans operalale by the applicatlon of pressu-re from th source iorreturning the valve elements to their positions where the zentralchamber is agaln in communication with the source but is prevented fromcommunicating with the chamber not counected to the source.

11. In a fluid pressure system a. source 01 pressure, a. fluidpressure-actuated device, a. chamber having a yieldable wall, valvemea.ns for trapping fluid under pressure in the actuated device wherebythe source of preSsure can 4 ber and said device in communication witheuch other, said valve means comprising a central chamber connected tothe actuating device. end chambers one of which is oonnecbed tb theourceof pressure und. the other to the yieldable Wall cha.mbger, aperturedwalis between the chambers packing cups positioned adjacent the walls onthe sides towar'd the centra1 ohnmber und each provided with a taperedaperture, a. spring interposed between.said cups, a. rod positioned insaid chambers und extendinz through the apertures 015 the .wa.lls andcups, said rod being provided with spaced talpered surfaces foraltemately engaging theapertures 01 the cups by longitudinalreciprocation o! the rod, a. piston secured to.the rod and positioned inthe end chamber which is connected to the yieldable Wall chamber, a.spring for biasing saicl piston1nd rod to a position where the aperturein the cup adJaceni: said piston is closed by the cooperating taperedportion o! the rod, means for moving said rod l'orwardly thereby unseatsah! last mentlon ed tapgred por tion sind causing the othertaperedportton of t he rod to close the tapered opening o! the cup with whichit cooperates, a.plston in the end chamber connected with the source,and means for connectlng sai d Inst named piston with the rod to movesa1d rod rearwardly only wheu in a. torwa.rd position und suflicientfluicl pressure in applied thereto by the source.

12. In a. fluid pressure system. a source f pressure, a. fluid-pressure-actuated device, va1ve mean.s for trapping fluia underpressure in the actua.ted device -whereby the source of pressure can bereieased without: release of the device, sa1d va.lve means comp1isipg acentral chamber counected to the actuating device, end chgmbers one o!which is connected to -che smxrce ot DressuIe. apertured Walls betweenthe chambers, packing cups positioned ad.iacent the Walls on the sidestoward the central chamber and each provided with a tapered aperture, aspring" interposed between said cups, a rod positioned in und. chanbersam! extending through the apertureg o! the walls a.nd cups, seid rodbeing prwided wlth spaced tapered surtachs tor alternately engag- 1ngthe apertures of the cups by lqngitudinal reciprocation ot'the rod apiston secured to th e rod und positioned in the end chamber which ':lsnot connected to the source. a. spring i'or biasing said piston und 1'odto a position wherethe aperture in the cup adjs'cent sald nisten 13cl0sed by themopemtinz taperegl portion 01 the rpd,

means tot moving said rod torwardly against the biss 01 the last namedsp ing 110 thereby unseat said last mentloned tapered pontion undvauslng the othger tap ired Portion. o1 the rod to clo3e the taperedopening o! the cup with which lt cooperstes. a. piston in the endchamber connected v vlth the aource, a.nd meam 1er connecting said lastnamed Diston with the rod to move said rod rearwardly only -When atorwara poeition und I3. In a. fluid pressure systexn. having a s0urce02 pressure und u fluid pressure actuated device connected thbrewlth a.coutrol v alve mechanism includinz v. vh-e elem'ent ior trapping fluidunder presstlre in. the actuated device and permitting release ofpressure from the source whout releasd 018 the fluid presmre in thedevice means operable at will tor causlng said control valve mechanismto be opersble. am! mea.ns aasoc:lated wlth sald contto1fialve mechanlsmf01' automatically releasing the trapp ad fluid pressure when fluidpresaure from the sonne is again developed und then released, said meansemhodying a. pisto n element to be acted an. by re-developed fluidpressure 1or positively movlng the valve elementto open position saidpiston element being so associated with the valve element that lt willbe operatively connected therewith und expable of being moved by there-developed fluid pressule only when the valve element: is closed 14.In a fluid pressure system, e. source ot pressure, a. fluia pressureactua.ted device, conduit means connecting the sbuxcg wich said device;valve means comprising s. va.1v e1eme:nt und stell! -associated withsah! conduit mean's tor preinting retum flow of fluid under pxeasre fromthe actuated dvice am! permittingthe pressttre 1mm the source tobereleased, man; tot rendering the closing 01 'sizid valve elementat.Will und means comprising a plston ussociated Wfl5h the stem 01 thevalve element for automatlcally causin: said element to agv.in assumg animperative posltion when fluid pressure 1mm the sburce is redeveloped.said pistofibeinz so arranged that all -1:he redeveloped pressure iseflective in moving the element to Imperative position und gaid valveelement when mo1red imperative position permltting the re-developedpressure to be (eifective in the fluia pressure actuated devlcesizficientfluidpressureisappliedthcretobytha

